We are working in Oracle 10g on Linux Debian 32 bit, A week back we had a problem that we were unable to access database by any tool of oracle locally as well as remotly in the morning, Everything was fine previously . when i try to write any command server was too slow and when i use sqlplus it is unable to run no reply then i use top command where i find CPU is too busy by USer using 40% and system using 25% in VMSTAT it was quite clear that there are runnable queue waiting for CPU time. But we could not find out the session which is doing so . When we kill Oracle user processes then CPU was fine after that i went to see Oracle alert log but no clue in that then i see ADDM report, Last snap shot was at 2:00 AM after an hour no snap was taken by Oracle. Now i do not know what happened to the database.

How to find about the status when no tool is wiorking and what can be the problem

Is there any one who can tell me that Oracle stop working and there is no clue in trace files then how to find out and secondly in the situation when oracle process is taking much resources and hogging CPU, how to find out the main processes

We are working in Oracle 10g on Linux Debian 32 bit, A week back we had a problem that we were unable to access database by any tool of oracle locally as well as remotly in the morning, Everything was fine previously . when i try to write any command server was too slow and when i use sqlplus it is unable to run no reply then i use top command where i find CPU is too busy by USer using 40% and system using 25% in VMSTAT it was quite clear that there are runnable queue waiting for CPU time. But we could not find out the session which is doing so . When we kill Oracle user processes then CPU was fine after that i went to see Oracle alert log but no clue in that then i see ADDM report, Last snap shot was at 2:00 AM after an hour no snap was taken by Oracle. Now i do not know what happened to the database.

How to find about the status when no tool is wiorking and what can be the problem.

No clue in trace file and could not find out the reaon it also happened two months back

But these document is related to Performance tuning when database is up.
I experience a problem that database itself stuck in processes and we had to kill processes of oracle. We were unable to even check whether database is up because it does not let us logging in the sqlplus. At this point of time how can any one check the bottleneck.

>write(1, "ORA-01017: invalid username/pass"..., 51) = 51
>it does not let us logging in the sqlplus
You would have a much better chance at being productive if you used a valid username/password combination.